The major aim of the proposed research program will be to follow, under controlled clinical trial settings, the changes occurring, with treatment in the cardiovascular systems of patients with simple moderate obesity. Clinical trial will involve a one-year double blind phase with phentermine-fenfluramine combination medication or placebo plus diet and a two-year open label follow-up phase. Approximately 120 patients with simple moderate obesity will be studied. The cardiovascular variables to be followed through the clinical trials will include blood pressue, heart rate, electrocardiogram, and lipid profile including total cholesterol, total triglyceride and low-density and high-density lipoproteins. The study will provide much new information. The long term efficacy of phentermine-fenfluramine combination used in conjunction with diet and behavior modification in the treatment of simple obesity will be brought out by the study. The study will also bring out the comparative efficacy of continuous versus intermittent targeted treatment.